What does “Intermittent Fasting” Mean?
Intermittent Fasting (IF, also called, in various permutations, The Warrior Diet, Lean Gains, 5:2, Eat Stop Eat) is an dietary intake pattern that has become popular in the last few years. There is a period of fasting – usually between 8-24 hours depending on the program you are adhering to, followed by a “refeed”.
How does it work?
Depends on the program. Here are some of the most popular IF plans:
- The Warrior Diet: One feeding per day, ideally 2 hours before bed, other meals are Paleo.
- Eat Stop Eat: 24 hour fast, once or twice a week. For example, dinner one day until dinner the next.
- Lean Gains: Restricting eating to an 8-hour window during the day, fasting the other 16.
- 5:2 Protocol: Eating 500-600 calories on two non-consecutive weekdays and normally the other 5 days.
Generally all programs recommend that you exercise in a fasted state, and some specify that you should be eating healthy food for your feeding periods (though not all demand that).
What does I.F. claim?
I.F. makes a lot of health and lifestyle claims. Some programs (like the Warrior Diet) claim that they are re-aligning our diet with our natural biological systems – much the way that cavemen would have operated. When you fast, your Human Growth Hormone levels (HGH) go way up, potentially leading to better fat loss and muscle growth. Additionally, your insulin levels and insulin sensitivity drop making your stored body fat a more accessible fuel source – hence the many claims that I.F. is a great weight loss tool. Fasting also releases norepinephrine which is a fat-burning hormone, increasing your metabolic rate. Because of these hormonal changes, I.F. adherents claim that fasting leads to:
- Increased Weight Loss: By restricting calories, as well as optimizing the timing and hormonal response to calories consumed.
- Decreased Insulin Resistance: Lowering blood sugar levels, and helping to protect against type 2 diabetes.
- Improved Heart Health: Intermittent fasting may reduce many factors in heart disease including LDL cholesterol, blood triglycerides, inflammatory markers.
- Anti-aging Benefits: A rodent study showed fasted rats living 36-83% longer than those unfasted. Additionally, fasting encourages cellular repair.
Are there any studies to back up those claims?
I.F. has been researched pretty thoroughly, though much of the research is new and much of it skews male. The studies that are being conducted that include female participants are in fact finding that I.F. may not be as beneficial for women as it is for men. For a very, very detailed account of the biological impact on women, you can check out these two sources:
Long story short – the insulin sensitivity benefits that I.F. offers to me seem to be reversed in women, actually worsening their blood sugar control. Even when done correctly and monitored, fasting can cause women to become hormonally unbalanced – resulting in depression, fatigue, bloating, headaches, and decreased productivity. In the extreme, I.F. can also lead to amenorrhea (missed or stopped periods), masculinization, and infertility.
Precision Nutrition suggests that I.F. might not be the right option for people who:
- Are married or have children
- Have performance oriented or client-facing jobs
- Compete in sport/athletics
- Are female
- Have a history of disordered eating
Since that refers to many, many derby skaters – derby and I.F. might not be a match made in heaven. Perhaps not surprisingly, I wasn’t able to find a current skater practicing I.F. to interview, so you’ll just have to check back in and see how I found the whole process.
Stay tuned for Part 2, where NoFair doesn’t get to eat, and then eats a bunch and shares recipes!
For further reading, check out: